Downloading attachments don't save

Just to ensure it was not a version issue, I installed the latest V2.XX Zimbra Desktop.

When I download a .jpg, a dialogue box appears asking me to save or open the file. I can open it (with my resident application ACDSee Pro), but i can't save it from there. And, if I try to simply save the file, it goes through the motions like it will save it in the desired directory, but does not actually save. So if I try to do the same save a second time, it does not advise me that I am overwriting the old file with a new one, because the old file doesn't save!